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Important: This documentation is about an older version. It's relevant only to the release noted, many of the features and functions have been updated or replaced. Please view the current version.

Open source

evaluate(pageFunction[, arg])

Returns the value of the pageFunction invocation.

ParameterTypeDefaultsDescription
pageFunctionfunction or stringFunction to be evaluated in the page context. This can also be a string.
argstring''Optional argument to pass to pageFunction

Returns

TypeDescription
anyThe value of the pageFunction invocation.

Example

JavaScript
import { browser } from 'k6/experimental/browser';
import { check } from 'k6/http';

export const options = {
  scenarios: {
    browser: {
      executor: 'shared-iterations',
      options: {
        browser: {
          type: 'chromium',
        },
      },
    },
  },
};

export default async function () {
  const page = browser.newPage();

  await page.goto('https://test.k6.io/browser.php');
  const dimensions = page.evaluate(() => {
    const obj = {
      width: document.documentElement.clientWidth,
      height: document.documentElement.clientHeight,
      deviceScaleFactor: window.devicePixelRatio,
    };
    return obj;
  });

  check(dimensions, {
    width: (d) => d.width === 1280,
    height: (d) => d.height === 720,
    scale: (d) => d.deviceScaleFactor === 1,
  });
}